Human behaviour and development under high‐altitude conditions

Virués‐Ortega, Javier; Garrido, Eduardo; Javierre, Casimiro; Kloezeman, Karen

doi:10.1111/j.1467-7687.2006.00505.x

Cited by 87 publications

(55 citation statements)

References 94 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For the behavior result, the high altitude group reacted slower than the low altitude group under all conditions. Consistent with other studies, the reaction time delay in the high altitude group might reflect altered sensoriperceptual processing 7,43,44 .…”

Section: Discussionmentioning

confidence: 99%

“…Sustained exposure to high altitude leads to cognitive decrement, such as impairment in attention, memory, judgment, and emotion 4 . Research has demonstrated that cognitive impairment due to altitude starts at 2,500 m above sea level [5][6][7] , because brain vulnerability to hypoxia increases beginning at 2,500 m 8 . Spatial attention may be particularly affected by high altitude exposure.…”

mentioning

confidence: 99%

“…In addition, the C1 component, which is thought to be generated within the primary visual or striate cortex, is attention sensitive under certain conditions and decreases in response to attended stimuli 28 . Task difficulty affects the relationship between high altitude and attention impairment, with difficult tasks resulting in a more obvious altitude effect 7,29 . For instance, Bonnon et al 29 found a greater discrepancy in performance between low and high altitude groups in a difficult compared with an easy task, indicating a greater decline in attention at high altitudes with the complex task.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Long-Term Exposure to High Altitude Affects Voluntary Spatial Attention at Early and Late Processing Stages

Wang

et al. 2014

Sci Rep

View full text Add to dashboard Cite

The neurocognitive basis of the effect of long-term high altitude exposure on voluntary attention is unclear. Using event related potentials, the high altitude group (people born in low altitude but who had lived at high altitude for 3 years) and the low altitude group (living in low altitude only) were investigated using a voluntary spatial attention discrimination task under high and low perceptual load conditions. The high altitude group responded slower than the low altitude group, while bilateral N1 activity was found only in the high altitude group. The P3 amplitude was smaller in the high altitude compared to the low altitude group only under high perceptual load. These results suggest that long-term exposure to high altitudes causes hemispheric compensation during discrimination processes at early processing stages and reduces attentional resources at late processing stages. In addition, the effect of altitude during the late stage is affected by perceptual load. More than 140 million people live permanently at high altitudes (.2,500 m above sea level) in North, Central, and South America, East Africa, and Asia 1 . As of 2006, approximately 12 million people live permanently on the Qinghai-Tibetan Plateau, and 71.14% of them live between 2,500 to 4,500 m. In addition, hundreds of thousands of people travel from lowland China to the Tibetan plateau every year; about 6 million Han lowland immigrants now live there permanently 2,3 . The largest and most important impact of living in a high altitude is hypoxia, which is caused by a reduction of oxygen in the air, and affects cognition. Sustained exposure to high altitude leads to cognitive decrement, such as impairment in attention, memory, judgment, and emotion 4 . Research has demonstrated that cognitive impairment due to altitude starts at 2,500 m above sea level [5][6][7] , because brain vulnerability to hypoxia increases beginning at 2,500 m 8 . Spatial attention may be particularly affected by high altitude exposure. First, the attentional impairment caused by exposure to high altitudes has been found in behavioral tests of visual attention (e.g., the digit symbol substitution test and visual search task) 9,10 , with slowed reaction times at higher altitudes. Second, previous studies have provided neuroimaging and electrophysiological evidence of the impact of high altitude exposure on the human brain [11][12][13] . In the neuroimaging study, brain areas related to attention processing-including the occipital lobe, parietal lobe, sensory-perceptual regions and frontoparietal attentional networks-were found to be affected by high altitude exposure 13,14 . In the electrophysiological study, the parietal distributed P3, which is crucially involved in maintaining attention, was the event-related potential (ERP) component most significantly affected by hypoxia 11,15 . Specifically, smaller and later P3 component responses have been reported for participants at high altitude than in those at the low altitudes, suggesting that cognitive abilities are sensitiv...

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Long-Term Exposure to High Altitude Affects Voluntary Spatial Attention at Early and Late Processing Stages

Wang

et al. 2014

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Neurophysiological functions such as event-related potentials, reaction time, psychomotor performances or cognitive processes have been reported to be aVected under exposure to high altitude (Virues-Ortega et al 2004;Virues-Ortega et al 2006). For example, Li et al (2000) investigated psychomotor performance and visual reaction time after acute exposure to hypoxia of 1 h duration at altitudes of 300 m (control), 2,800, 3,600, and 4,400 m. The results showed no diVerences in performance at 2,800 m, but tremor decreased signiWcantly at 3,600 and 4,400 m. Consequently, the literature suggests that the critical altitude for changes in higher cognitive functioning appears to lie between 4,000 and 5,000 m. It has been shown that there is little variation at 3,800 m, but a marked deterioration in cognitive ability occurs at 5,000 m (Nelson 1982).…”

mentioning

confidence: 99%

Effects of acute hypoxia on postural and kinetic tremor

et al. 2010

View full text Add to dashboard Cite

Human physiological tremor is a complex phenomenon that is modulated by numerous mechanical, neurophysiological, and environmental conditions. Researchers investigating tremor have suggested that acute hypoxia increases tremor amplitude. Based on the results of prior studies, we hypothesized that human participants exposed to a simulated altitude of 4,500 m would display an increased tremor amplitude within the 6-12 Hz frequency range. Postural and kinetic tremors were recorded with a laser system in 23 healthy male participants before, during, and after 1 h of altitude-induced hypoxia. A large panel of tremor characteristics was used to investigate the effect of hypoxia. Acute hypoxia increased tremor frequency content between 6 and 12 Hz during both postural and kinetic tremor tasks (P < 0.05, F = 6.142, Eta(2) = 0.24 and P < 0.05, F = 3.767 Eta(2) = 0.14, respectively). Although the physiological mechanisms underlying the observed changes in tremor are not completely elucidated yet, this study confirms that acute hypoxia increases tremor frequency in the 6-12 Hz range. Furthermore, this study indicates that changes in physiological tremor can be detected at lower hypoxemic levels than previously reported (blood saturation in oxygen = 80.9%). The effects of hypoxia mainly result from a cascade of events starting with the activation of the hypothalamic-pituitary-adrenal axis causing in turn an increase in catecholamine release, leading to an augmentation of tremor amplitude in the 6- to 12-Hz interval and heart rate increase.

show abstract

“…having the ability to receive through the senses diverse images, impressions or external sensations, or to understand and to know something (Pinel). It is commonly believed that attention and perception are hardest to reach in communities that reside at high altitudes above the sea level, since living in high altitudes exposes our body to lower oxygen pressure (Virués-Ortega et al, 2006).…”

Section: Discussionmentioning

confidence: 99%